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Deepest Leaves Sum (M) 题目 Given the root of a binary tree, return the sum of values of its deepest leaves. Example 1: Input: root = [1,2,3,4,5,null,6, 阅读全文
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Longest Increasing Path in a Matrix (H) 题目 Given an m x n integers matrix, return the length of the longest increasing path in matrix. From each cell, 阅读全文
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Verifying an Alien Dictionary (E) 题目 In an alien language, surprisingly they also use english lowercase letters, but possibly in a different order. Th 阅读全文
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Determine if String Halves Are Alike (E) 题目 You are given a string s of even length. Split this string into two halves of equal lengths, and let a be 阅读全文
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Minimum Operations to Make Array Equal (M) 题目 You have an array arr of length n where arr[i] = (2 * i) + 1 for all valid values of i (i.e. 0 <= i < n) 阅读全文
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Global and Local Inversions (M) 题目 We have some permutation A of [0, 1, ..., N - 1], where N is the length of A. The number of (global) inversions is 阅读全文
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Design Circular Queue (M) 题目 Design your implementation of the circular queue. The circular queue is a linear data structure in which the operations a 阅读全文
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Ones and Zeroes (M) 题目 You are given an array of binary strings strs and two integers m and n. Return the size of the largest subset of strs such that 阅读全文
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Palindrome Linked List (E) 题目 Given a singly linked list, determine if it is a palindrome. Example 1: Input: 1->2 Output: false Example 2: Input: 1->2 阅读全文
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Stamping The Sequence (H) 题目 You want to form a target string of lowercase letters. At the beginning, your sequence is target.length '?' marks. You al 阅读全文